not true.
You can unroot.
Search on XDA, there is a download that will covert your phone back.It's like the original rom but it unroots and returns everything back. I tried it when i was first making a gold card and fkd up so I went back and ran this rom and my phone was un rooted.

I thought that rooting doesn't involve messing with the bootloader, is not true. You might not do it with one click, but manually with the terminal app if you need to send it back for repair or warranty issue. Look on the XDA for unrooting, not that difficult.